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  • Presentation: 2020-06-08 09:15 Högskolan Dalarna, Borlänge
    Warneryd, Martin
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    The social power grid: The role of institutions for decentralizing the electricity grid2020Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The world’s existing electricity grids face several challenges if they are to continue to provide a stable supply in the future. Aging electricity grids and the massive implementation of renewable sources require a different flexibility and robustness of future grids. Large amounts of renewable sources are implemented locally and on a small scale, increasing pressure on distribution grids to manage variable generation and bi-directional power flows. A decentralized electricity system includes both new technological designs as well as social re-organizations where prosumers become more prominent in the development and responsibilities of the electricity system. The existing centralized electricity system is fundamentally different from the decentralized, and the transformation requires an institutional framework which support the logics of decentralized technologies and organizations. Some technologies which are relevant for a decentralized electricity system include solar PV and MGs. The aim of the thesis is to investigate how the transformation toward a decentralized electricity system affects and is affected by informal institutions among relevant actors, specifically prosumers, and formal institutions related to the existing electricity system. To guide the aim this research uses a conceptual framework stemming from the theoretical field of sustainability transitions with a special emphasis on institutions. The results show that a wide variety of experienced values enhances the positive experiences with solar PV technology and thus prosumers increase their engagement and responsibilities in their own electricity system. Moreover, the values are used to enhance the positive narrative of the niche and thereby increase the attractiveness for external actors. In the formative developing field of community MGs, institutions play an important role. Informal institutions shape the formal institutional development, which also influences the informal institutions in return, by enhancing opportunities for certain groups, such as the energy democracy movement, to reach out with their message. Thus, it is concluded that informal institutions play a significant role in the development of a decentralized electricity system, affecting several niche development parameters and influencing the initial trajectories to further develop. Moreover, it is concluded that institutional developments are crucial for the development of community MGs and that informal institutional developments within communities are shaping the formal institutional developments in the sector.    

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  • Presentation: 2020-06-15 09:00 Västerås Campus (+ Online/Zoom), Västerås
    Gu, Rong
    Mälardalen University, School of Innovation, Design and Engineering.
    Automatic Model Generation and Scalable Verification for Autonomous Vehicles: Mission Planning and Collision Avoidance2020Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Autonomous vehicles such as mobile driver-less construction equipment bear the promise of increased safety and industrial productivity by automating repetitive tasks and reducing manual labor costs. These systems are usually involved in safety- or mission-critical scenarios, therefore they require thorough analysis and verification. Traditional approaches such as simulation and prototype testing are limited in their scope of verifying a system that interacts autonomously with an unpredictable environment that assumes the presence of humans and varying site conditions. Methods for formal verification could be more suitable in providing guarantees of safe operation of autonomous vehicles within specified unpredictable environments. However, employing them entails addressing two main challenges: (i) constructing the models of the systems and their environment, and (ii) scaling the verification to the incurred model complexity. We address these two challenges for two essential aspects of autonomous vehicle design: mission planning and collision avoidance. Though inherently different, communication between these two aspects is necessary, as the information obtained from verifying collision avoidance can help to improve the mission planning and vice versa. Finding a solution that addresses both mission planning and collision avoidance modeling and verification, while decoupling them for solution maintainability is one crux of this study. Another one deals with demonstrating the applicability and scalability of the proposed approach on complex and industrial-level systems.

    In this thesis, we propose a two-layer framework for mission planning and verification of autonomous vehicles. The framework separates the modeling and computing mission plans in a discrete environment, from the vehicle movement within a continuous environment, in which collision avoidance algorithms based on dipole fields are proven to ensure safe behavior. We call the layer for mission planning, the "static layer", and the other one the "dynamic layer". Due to the inherent difference between the layers, we use different modeling and verification approaches, namely: (i) the timed automata formalism and the UPPAAL model checker to compute mission plans for the autonomous vehicles, and (ii) hybrid automata and statistical model checking using UPPAAL Statistical Model Checker to verify collision avoidance and safe operation. We create model-generation algorithms, based on which we develop tool support for the static layer, called TAMAA (Timed-Automata-Based Planner for Autonomous Agents). The tool enables the designers to configure their systems and environments in a graphical user interface, and utilize formal methods and advanced path-planning algorithms to generate mission plans automatically. TAMAA also integrates reinforcement learning with model checking to alleviate the state-space explosion problem when the number of vehicles increases. We create a hybrid model for the dynamic layer of the framework and propose a pattern-based modeling method for the embedded control systems of the autonomous vehicles to ease the design and facilitate reuse. We validate the proposed framework and design method on an industrial use case involving autonomous wheel loaders, for which we verify invariance, reachability, and liveness properties.

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  • Presentation: 2020-09-02 13:15 Lambda + Online, Västerås, Sweden
    Sheikh Bahaei, Soheila
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    A Framework for Risk Assessment in Augmented Reality-equipped Socio-technical Systems2020Licentiate thesis, comprehensive summary (Other academic)